Transmission integrated power take off for commercial vehicle transmission

ABSTRACT

A rear mount power take-off for a transmission includes a housing assembly configured to be mounted in an opening in the transmission. A power take-off shaft includes an externally splined end extending into an opening in the housing assembly and is configured to be driven by a component of the transmission. A guide sleeve is received in the housing assembly and includes an exterior shoulder opposing an interior retaining shoulder of the housing assembly, the guide sleeve further including an interior shoulder. A spring biases the guide sleeve against the interior retaining shoulder of the housing assembly. A coupler sleeve is secured to an interior of the guide sleeve and includes a first internal spline for selective engagement with the externally splined end of the power take-off input shaft and a second internal spline configured to engage a power take-off device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 17/587,767, filed Jan. 28, 2022, which is a divisional applicationof U.S. application Ser. No. 16/950,775, filed Nov. 17, 2020, whichclaims the benefit of U.S. Provisional Application No. 62/942,710, filedon Dec. 2, 2019. The entire disclosures of the above applications areincorporated herein by reference.

FIELD

The present disclosure relates to an integrated power take off for acommercial vehicle transmission.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

Transmissions serve a critical function in translating power provided bya prime mover to a final load. The transmission serves to provide speedratio changing between the prime mover output (e.g., a rotating shaft)and a load driving input (e.g., a rotating shaft coupled to wheels, apump, or other device responsive to the driving shaft). The ability toprovide selectable speed ratios allows the transmission to amplifytorque, keep the prime mover and load speeds within ranges desired forthose devices, and to selectively disconnect the prime mover from theload at certain operating conditions.

Transmissions are subjected to a number of conflicting constraints andoperating requirements. For example, the transmission must be able toprovide the desired range of torque multiplication while still handlingthe input torque requirements of the system. Additionally, from the viewof the overall system, the transmission represents an overheaddevice—the space occupied by the transmission, the weight, and interfacerequirements of the transmission are all overhead aspects to thedesigner of the system. Transmission systems are highly complex, andthey take a long time to design, integrate, and test; accordingly, thetransmission is also often required to meet the expectations of thesystem integrator relative to previous or historical transmissions. Forexample, a reduction of the space occupied by a transmission may bedesirable in the long run, but for a given system design it may be moredesirable that an occupied space be identical to a previous generationtransmission, or as close as possible.

Previously known transmission systems suffer from one or more drawbackswithin a system as described following. To manage noise, robustness, andstructural integrity concerns, previously known high output transmissionsystems use steel for the housing of the transmission. Additionally,thrust loads through the transmission, noise generated by gears, andinstallation issues such as complex gear timing issues, require a robustand potentially overdesigned system in the housing, bearings, and/orinstallation procedures. Accordingly, there remains a need forimprovements in the design of high output transmissions, particularlytruck transmissions.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

The present disclosure is directed to a rear mount power take-off for atransmission includes a housing assembly configured to be mounted in anopening in the transmission. A power take-off shaft includes anexternally splined end extending into an opening in the housing assemblyand is configured to be driven by a component of the transmission. Aguide sleeve is received in the housing assembly and includes anexterior shoulder opposing an interior retaining shoulder of the housingassembly, the guide sleeve further including an interior shoulder. Aspring biases the guide sleeve against the interior retaining shoulderof the housing assembly. A coupler sleeve is secured to an interior ofthe guide sleeve and includes a first internal spline for selectiveengagement with the externally splined end of the power take-off inputshaft and a second internal spline configured to engage a power take-offdevice.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a perspective view of a transmission according to theprinciples of the present disclosure;

FIG. 2A is a horizontal cross-sectional view of the transmissionassembly according to the principles of the present disclosure;

FIG. 2B is a vertical cross-sectional view of the transmission assemblyaccording to the principles of the present disclosure;

FIG. 3 is a partial cross-sectional view of the countershaft gear trainsystem of the present disclosure with the housing removed forillustrative purposes;

FIG. 4 is a left side rear perspective view of a main transmissionhousing according to the principles of the present disclosure;

FIG. 5 is a right side rear perspective view of the main transmissionhousing according to the principles of the present disclosure;

FIG. 6 is a bottom side rear perspective view of the main transmissionhousing according to the principles of the present disclosure;

FIG. 7 is cutaway perspective view of the main transmission housingaccording to the principles of the present disclosure;

FIG. 8 is a front perspective view from the right side of the machinedintermediate plate of the transmission enclosure;

FIG. 9 is a front perspective view from the left side of the machinedintermediate plate of the transmission closure having reverse idlergears mounted thereto;

FIG. 10 is an exploded perspective view of a PTO driven gear supportassembly;

FIG. 11 is a cross-sectional view of the PTO driven gear supportassembly shown in FIG. 10 ;

FIG. 12 is a cross-sectional view of a rear mount power take-off unit;and

FIG. 13 is a cross-sectional view of a power take-off device connectedto a rear mount power take-off unit according to the principles of thepresent disclosure.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

With reference to FIG. 1 , a perspective view of a transmission 10 isshown including a main housing 12, an intermediate plate 14 and a rearhousing 16. The transmission 10 is assembled with the intermediate plate14 assembled to a rear end of the main housing 12 and the rear housing16 is mounted to the intermediate plate 14. An integrated actuatorhousing 18 is mounted to the main housing 12.

As shown in FIG. 2A, the transmission 10 is depicted schematically in ahorizontal cutaway view. The example transmission 10 is capable ofproviding power throughput from a prime mover (not shown) interfacingwith a clutch unit 22 (schematically shown) to an input shaft 23, fromthe input shaft 23 to an extension shaft 24, from the extension shaft 24to a main shaft portion 26, from the main shaft portion to a range shaftportion 28, and from the range shaft portion 28 to an output shaftassembly 30.

The example transmission 10 is operable to adjust torque multiplicationratios throughout the transmission, to engage and disengage the clutchunit 22 from the prime mover (not shown), and/or to position thetransmission 10 into a neutral position wherein, even if the clutch unit22 is engaged to the prime mover, torque is not transmitted from theclutch unit 22 to the output shaft assembly 30.

With further reference to FIGS. 2A and 2B, a clutch engagement yoke 32is provided for engagement of the clutch unit 22 with the prime mover.The example clutch engagement yoke 32 is operationally coupled at afirst end to a clutch actuator. In certain embodiments of the presentdisclosure, any type of clutch actuation may be utilized, including aconcentric clutch actuator (not shown) and/or another type of linearclutch actuation device.

The example transmission 20 includes a splitter section 33 a, a main boxsection 33 b and a range gear section 33 c to provide multiple gearratios. The splitter section 33 a includes a first splitter gear 34, asecond splitter gear 36 and a third splitter gear 38 each selectivelycoupled to the extension shaft 24. The inclusion of the splitter gears34, 36, 38 allow for additional distinct gear ratios provided by theextension shaft 24. The splitter gear 34 can be rotatably engaged withthe extension shaft 24 by a first synchronizer clutch 35, while thesplitter gears 36 and 38 can be selectively rotatably engaged with theextension shaft 24 by a second two-sided synchronizer clutch 39.

The main box section 33 b of the example transmission 20 furtherincludes a number of main box gears 40, 42, 44 selectively coupled tothe main shaft portion 26. The main box gear 40 can be rotatably engagedwith the main shaft 26 by a third synchronizer clutch 41, while the mainbox gears 42 and 44 can be selectively rotatably engaged with the mainshaft 26 by a fourth two-sided synchronizer clutch 45.

The range gear section 33 c of the example transmission 20 furtherincludes a planetary gear assembly 46 that couples the range shaftportion 28 to the output shaft assembly 30 through at least twoselectable gear ratios between the range shaft portion 28 and the outputshaft assembly 30. In particular, as is known in the art, the planetarycarrier of the planetary gear assembly 46 can be engaged to the sun gearto provide a drive ratio of 1:1 or disengaged to provide a gearreduction through the planetary system.

The example transmission 20 further includes at least one, andpreferably two countershafts 48 a, 48 b, the countershafts 48 a, 48 bhaving three aligning gears 50, 52, 54 within the splitter section 33 aand drivingly engaged with the respective first, second and thirdsplitter gears 34, 36, 38 on the extension shaft 24. The countershafts48 a, 48 b further include three aligning gears 56, 58, 60 within themain box section 33 b and drivingly engaged with the respective first,second and third main box gears 40, 42, 44 selectively coupled to themain shaft portion 26. With the three gears in the splitter section 33a, the three gears in the main box section 33 b and the two gear ratiosprovided by the range gear section 33 c, the transmission 20 provides a3×3×2 transmission architecture that is operable to provide 18 practicaland functional gear ratios. The number and selection of gears dependsupon the desired number of gear ratios from the transmission.

The transmission 10 includes a pair of reverse idler gears 62 (bestshown in FIG. 9 ) that engage with the aligning gears 60 of thecountershafts 48 a, 48 b and with the main box gear 44 of the main shaftportion 26. The countershaft(s) 48 a, 48 b thereby selectively transmitforward or reverse power between the extension shaft 24 and the mainshaft portion 26, depending upon which gears are rotationally fixed (viaclutches) to the extension shaft 24 and/or the main shaft portion 26.

As shown in the vertical cross-sectional view of the transmission 10 inFIG. 2B, the transmission further includes a PTO drive gear 70 fixed tothe extension shaft 24 for rotation therewith. The PTO drive gear 70 isdisposed between the first splitter gear 34 and the second splitter gear36 and is engaged with a PTO driven gear 72 that is mounted to a PTOshaft 74.

As best shown in FIGS. 10 and 11 , the PTO shaft 74 and the PTO drivengear 72 are each supported by a PTO pillow block housing 76 thatsupports a pair of roller bearings 78 that rotatably support a PTO gearshaft 80. The PTO driven gear 72 is connected to the PTO gear shaft 80by a woodruff key 82. The PTO gear shaft 80 includes a pair of annulargrooves 8 for receiving a pair of retaining rings 84 to secure the PTOgear shaft 80 within the roller bearings 78. As best shown in FIG. 11 ,the PTO pillow block housing 76 can include a recessed annular groove 86for receiving a snap ring 87 to secure the roller bearings 78 within thePTO pillow block housing 76. The PTO pillow block housing 76 is mountedto and supported by a base frame 88, including four mounting ears 90with threaded apertures 92 for receiving a plurality of mounting bolts94 that extend through apertures 96 in the PTO pillow block housing 76.With continued reference to FIG. 2B, the PTO shaft 74 is supported atits forward end by the PTO pillow block housing 76 and is supported atits rear end by a bearing 98 supported within an aperture 99 (FIGS. 8and 9 ) in the intermediate plate 14.

With reference to FIGS. 4-7 , the main housing 12 includes a one-piecegenerally annular wall structure 100 made from cast aluminum. A frontend 102 of the main housing 12 can define a clutch chamber 104 (FIGS.2A, 2B) for receiving the clutch engagement yoke 32 of the clutch unit22. A rear end 106 of the main housing 12 defines a transmission mainchamber 108 for receiving the second main shaft portion 26 and the rangeshaft portion 28 and the countershafts 48 a, 48 b. As best shown inFIGS. 2A, 2B and 7 , a partition wall 109 is disposed between the clutchchamber 104 and the transmission main chamber 108 and is integrallyformed with the one-piece generally annular wall structure 100. Thepartition wall 109 includes a plurality of openings 109 a, 109 b, 109 c(FIG. 2A) for receiving and supporting the extension shaft 24 and afirst end of the countershafts 48 a, 48 b.

The intermediate plate 14 includes a plurality of openings 14 a, 14 b,14 c for receiving and supporting the main shaft 26 and the range shaft28 and a second end of the countershafts 48 a, 48 b. The extension shaft24 is supported at a forward end by a bearing 150 disposed in theopening 109 a in the partition wall 109. A rearward end of the extensionshaft is supported by roller bearing 152 disposed within a bore in therange shaft portion 28. A forward end of the range shaft portion 28 issupported within the opening 14 a of the intermediate plate 14 by abearing assembly 154. The main shaft 26 is rotatably supported on theextension shaft 24. A rear end of the main shaft has exterior splineswhich are engaged with interior splines on a forward end of the rangeshaft 28 radially within the bearing support 154.

With reference to FIG. 3 , the extension shaft 24 includes interiorsplines 804 which are connected to exterior splines 23 a of the inputshaft 23. A forward end of the extension shaft 24 a is supported by thebearing assembly 150. The forward end of the extension shaft 24 a alsoincludes an exterior spline 806 which is connected to an interior spline308 of a clutch hub 810. The first splitter gear 34 is loosely supportedon the extension shaft 24 by a needle bearing 812 and a second splittergear 36 is loosely supported on the extension shaft 24 by a needlebearing 814. The first splitter gear 34 is disposed against the clutchhub 810 and against the PTO drive gear 70. The second splitter gear 36is disposed against the PTO drive gear 70 and against a clutch hub 816that is splined to the extension shaft 24. A thrust washer 818 isdisposed between the clutch hub and a first thrust bearing 800 havingcylindrical rollers 820 that are disposed against a thrust race 822. Thethird splitter gear 38 is supported with radial clearance on the thrustrace 822. A sliding clutch 824 is supported on the clutch hub 816 and isengageable with the second splitter gear 36 and the third splitter gear38. A second thrust bearing 826 having cylindrical rollers 828 isdisposed against the thrust race 822. A thrust washer 830 is disposedagainst the second thrust bearing 826 and is disposed against a race832. The race 832 includes a tapered rear surface that is disposedagainst a spherical washer 836. The spherical washer 836 is disposedagainst a clutch hub 838 and main shaft 26. Clutch hub 838 is splined tothe main shaft 26. The two-sided slide clutch 41 is mounted to theclutch hub 838.

The range gear shaft 28 includes interior splines 842 that engageexterior splines 844 of the main shaft 26. The main box gear 40 islocated by the clutch hub 838 and washer 850 and is engaged thereto bythe slide clutch 41. The second main box gears 42 44 is selectivelyengaged to the main shaft 26 and located by washer 850 and clutch hub846 that supports the sliding clutch 45. The third main box gear isselectively engaged to the main shaft 26 and is located by washer 852,spacer 854 and washer 856 and clutch hub 846 that supports the slidingclutch 45.

With reference to FIGS. 4-6 , the one-piece generally annular wallstructure 100 of the main housing 12 has a forward mounting flange 110and a rearward mounting flange 112 each having a plurality of aperturesor bores 114 for receiving fasteners therein. The annular wall structure100 can have a wall thickness of between 5.0 and 7.0 mm and preferably6.0 mm in order to provide a reduced weight aluminum housing.

In order to further strengthen the annular wall structure 100 aplurality of axially extending raised ribs 116 can extend longitudinallyfrom the front end 102 to the rear end 106 of the main housing 12. Theaxially extending raised ribs 116 provide part structure, reducefrequencies of the large panels of the main housing 100, and supportmaterial flow throughout the structure during casting of the mainhousing 100. In addition, a plurality of angularly extending raised ribs118 extend diagonally between adjacent ones of the plurality of axiallyextending raised ribs 116. By “diagonally,” it is meant that theplurality of angularly extending raised ribs 118 extend at an acute(non-perpendicular) angle from the axially extending raised ribs 116.The angularly extending raised ribs 118 provide part structure byconnecting the longitudinal ribs 116 and further aid in material flowduring casting of the main housing 100 thereby reducing turbulence andmitigating porosity.

As shown in FIG. 4 , the one-piece generally annular wall structure 100can include a top wall portion 120, a left side wall portion 122, aright side wall portion 124, and a bottom wall portion 126. The top wallportion 120 can include an actuator interface opening 128 with anactuator wall structure 130 extending radially outward from the top wallportion 120 of the generally annular wall structure 100. The actuatorwall structure 130 can include a plurality of bores 132 for receivingfasteners for securing the actuator housing 18 within the actuatorinterface opening 128. As best shown in FIG. 6 , the bottom wall portion126 can include a PTO interface opening 136 with a PTO wall structure138 extending radially outward from the bottom wall portion 126 of thegenerally annular wall structure 100. The PTO wall structure 138 caninclude a plurality of bores 140 for receiving fasteners for securing aPTO cover 142 over the PTO interface opening 136. As shown in FIG. 2B,the PTO cover 142 can include a cover body configured to envelope aportion of the PTO driven gear 72 so as to be in close proximityin-front, in-back and peripherally around a portion of the PTO drivengear 72 to limit oil and air resistance (i.e., windage) to the rotatingPTO driven gear 72.

With reference to FIG. 7 , a cut section of the main housing 12 is shownincluding a plurality of waves 144 disposed in the bottom wall portion126 and the right sidewall portion 124. The waves 144 define anundulating surface and extend axially along the generally annular wallstructure 100 and break up large flat panels of the wall portions 126,124 by providing additional strength and reduced frequencies.

The design of the aluminum main housing 12 provides for a reduced weighthousing with the required strength and noise reduction. The aluminummain housing 12 is also economically cast-able.

With reference to FIGS. 8 and 9 , the intermediate plate 14 of thetransmission housing 10 will now be described. As shown in FIG. 8 , theintermediate plate 14 includes a plate-like base 200 having a peripheralflange portion 202 extending around the plate-like base 200. Theplate-like base 200 includes the center opening 14 a for receiving thebearing 154 (best shown in FIG. 2B) for supporting the extension shaft24, first main shaft portion 26 and second main shaft portion 28. Theplate-like base 200 includes a pair of openings 14 b, 14 c laterallyoffset from the center opening 14 a for receiving bearings 210 forsupporting the countershafts 48 a, 48 b. The intermediate plate 14further includes two pairs of axially spaced reverse idler supportbosses 212 a, 212 b for supporting the pair of reverse idler gears 62,as best shown in FIG. 9 . The support bosses 212 a are supported by abridge wall including a pair of side ribs 216, a mid-wall 218 andadditional structural ribs 220 that extend from the mid wall 218 to theperipheral flange 202.

As shown in FIG. 9 , the reverse idler support bosses 212 a, 212 b eachinclude openings 226 that supports a reverse idler shaft 228 thatsupports the reverse idler gear 62. The reverse idler gears 62 eachengage one of the aligning gears 60 of the countershafts 48 a, 48 b andwith the gear 44 of the first main shaft portion 26.

With reference to FIG. 2B, the PTO shaft 74 is drivingly connected to animpeller of a transmission lube pump 230 that is mounted to theintermediate plate 14. The transmission lube pump 230 is driven by thePTO shaft 74 and supplies lubrication from an oil sump 232 at a bottomof the transmission housing 12, 14, 16 to interior passages 234 withinthe extension shaft 24 and range shaft 28 as well as other components ofthe transmission.

With continued reference to FIG. 2B, the end of the PTO shaft 74 canfurther be engaged with a rear mount PTO 240 extending from the rearhousing 16.

With reference to FIGS. 12 and 13 , the rear mount PTO 240 is shownincluding a PTO housing 242 having a PTO input shaft 244 rotatablysupported by a bearing 246. The PTO input shaft 244 includes an externalspline 248 that can be engaged with a first internal spline 250 of acoupler sleeve 252. The coupler sleeve 252 is disposed within the PTOhousing 242 and is biased by a spring 254 toward a disengaged position.The coupler sleeve 252 is connected to a guide sleeve 256 slidablyreceived within a retainer 258 that limits axial movement of the guidesleeve 256.

With reference to FIG. 13 , as a power take-off device 260 is engagedwith the rear mount PTO 240, a splined shaft 262 is inserted into asecond internal spline 264 of the coupler sleeve 252 in order to providea driving connection to the power take-off device 260. The couplersleeve 252 can be pressed by the splined shaft 262 or by anothermechanism against the biasing force of the spring 254 into engagementwith the external spline 248 of the PTO input shaft 244. In particular,the splined shaft 262 can include an external shoulder 266 that canengage the coupler sleeve 252 and press the coupler sleeve 252 intoengagement with the PTO input shaft 244. When there is no PTO device 260mounted to the rear mount PTO 240, the PTO input shaft 244 does notengage the coupler sleeve 252 and freewheels relative to the couplersleeve 252. The PTO input shaft 244 can be integrally formed with thePTO shaft 74 or can be connected therewith by splines 268 or other knownconnecting systems.

The present disclosure utilizes a short input shaft 23 that is alignedwith the engine flywheel pilot bearing and concentrically splined to theextension shaft 24 that is coaxial to the transmission 10. The threefront splitter drive gears 34, 36, 38 are couple-able to the extensionshaft 24 via synchronizer clutches 35 and 39. The extension shaft 24 maybe constructed from one piece or from multiple joined pieces as bestsuits the manufacturing and assembly process and so that the extensionshaft is rigid. The thrust roller bearing races 800, 826 are maintainedon the transmission center axis to minimize radial displacement whilethe three splitter drive gears 34, 36, 38 and main shaft gears 40, 42,44 are permitted to radially float for the twin countershaft design. Theindependent PTO drive gear 70 is directly affixed to the extension shaft24 and utilizes an independent drive gear/shaft for PTO output means.The PTO output can be in at least two forms including the bottom mountgear meshing interface form or the rear mount shaft coupled interfaceform. This configuration affords a single speed ratio of the powertakeoff (PTO) with respect to engine RPM. The PTO rear shaft is alsoconfigured to drive the transmission lube pump at a single speed ratiowith respect to the engine speed. This transmission lube pump is thenactive in all transmission states when the main input disk clutch 22 isengaged with the engine.

According to a further aspect of the present disclosure, the powertakeoff system utilizes the PTO drive gear 70 directly affixed to theextension shaft 24 and an independent driven gear/shaft 72/74 for thepower takeoff output means. This configuration provides for the powertakeoff mode to be available in all transmission ratios.

According to yet another aspect of the present disclosure, each end ofthe extension shaft 24 is configured to be supported by bearings and/orconcentric shafts to observe the radial PTO mode loading. The radial PTOmode loads onto the extension shaft 24 have insignificant interactionwith gear ratio loads when in PTO mobile mode. The PTO driven gear isaffixed to a shaft mounted on bearings which in turn are directly orindirectly affixed to the transmission housing.

According to still another aspect of the present disclosure, theextension shaft is incorporated with significant radial clearance withthe front two splitter drive gears 34, 36 to accommodate radial float.The radial float is required for the unloaded splitter drive gear whenthe opposite splitter drive gear is in the operating load path. The PTOradial loads observed by the affixed extension shaft 24 are independentof splitter gear selection.

The present disclosure incorporates two thrust bearings, one thrustbearing 800 between the second and third splitter drive gears 36, 38and, a second thrust bearing 826 between the third splitter gear 38 andthe main shaft 26 to address helical gearing thrust loads and a mainshaft ball bearing to accommodate thrust for engine braking torque mode.Thrust for engine braking torque mode may also be accommodated by asplitter section thrust bearing, but is dependent upon the operatingratio. The present disclosure provides significant radial floatincorporated into the interface of the third splitter gear 38 withrespect to its mating thrust bearing race.

The present disclosure also incorporates an expanded center distance forthe PTO driven gear output to accommodate output and yoke or outputflange radial clearance with the rear mount PTO output yoke or directmount pump. This PTO expanded center distance is independent ofcountershaft center distance.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, engaged, connected, or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to,” or “directly coupled to” another elementor layer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A rear mount power take-off for a transmission,comprising: a housing assembly configured to be mounted in an opening inthe transmission; a power take-off shaft having an externally splinedend extending into an opening in the housing assembly and configured tobe driven by a component of the transmission; a guide sleeve received inthe housing assembly and including an exterior shoulder opposing aninterior retaining shoulder of the housing assembly, the guide sleevefurther including an interior shoulder; a spring biasing the guidesleeve against the interior retaining shoulder of the housing assembly;a coupler sleeve secured to an interior of the guide sleeve and having afirst internal spline for selective engagement with the externallysplined end of the power take-off input shaft and a second internalspline configured to engage a power take-off device.
 2. The rear mountpower take-off for a transmission according to claim 1, wherein theguide sleeve and coupler sleeve are axially movable relative to thehousing assembly to engage the first internal spline of the couplersleeve to the externally splined end of the power take-off input shaft.3. The rear mount power take-off for a transmission according to claim1, wherein the power take-off input shaft is supported by a bearingassembly that is configured to be received in the transmission.
 4. Therear mount power take-off for a transmission according to claim 1,wherein the spring is seated against the housing assembly.
 5. The rearmount power take-off for a transmission according to claim 1, whereinthe coupler sleeve is pressed by the power take-off device against abiasing force of the spring to engage the first internal spline with theexternally splined end of the power take-off input shaft.
 6. The rearmount power take-off for a transmission according to claim 5, whereinwhen there is no power take-off mounted to the rear mounted powertake-off, the externally splined end of the power take-off shaft doesnot engage the first internal spline of the coupler sleeve.